A medical suture and ligature instrument for suturing or ligaturing a biological tissue in a body while observing the biological tissue by the use of an endoscope is known, which includes a sheath to be inserted through a channel of the endoscope, an operating wire inserted into the sheath to extend and retract, and a medical suture and ligature tool to be locked to a hook at a distal end of the operating wire. The medical ligature tool has a ligature wire of a loop shape and the size of the loop can be adjusted by allowing a stopper to extend and retract along the ligature wire. A folding-back portion to be locked to the hook is formed in the proximal end portion of the ligature wire. At the time of ligaturing a pathological lesion portion, the loop is hooked to the pathological lesion portion, the hook is made to retract, and the diameter of the loop is reduced, thereby binding the pathological lesion portion tight. Thereafter, the ligature wire is cut between the portion binding the pathological lesion portion tight and the folding-back portion and the ligature wire is detained in the body in a state where the biological tissue is bound tight.
Here, a medical ligature tool is also known in which a cutting member is disposed outside of a sheath into which an operating wire is inserted so as to extend and retract and a holding member for receiving the cutting member while holding the ligature wire between a folding-back portion and a stopper is disposed in the medical ligature tool, so as to perform as a series of operations an operation of tightly binding and ligaturing a pathological lesion portion with the medical ligature tool and an operation of separating the medical ligature tool from the operating wire (for example, see Patent Document 1). The holding member has a cylindrical shape through which the ligature wire is inserted and an annular protrusion is incorporated in a substantially central portion in an axial direction thereof. The portions closer to the distal and the proximal ends with respect to the protrusion, each have a hole through which the ligature wire can be inserted. The ligature wire is inserted inside via a distal opening of the passage penetrating the holding member, passes through the distal hole, is drawn along the outer periphery of the protrusion in the longitudinal direction, extends into the holding member through the proximal hole, and then is drawn out of the proximal opening. In such a medical ligature tool, a pathological lesion portion is tightly bound, the cutting member is made to advance, and the ligature wire is cut by interposing the ligature wire between the protrusion and the cutting member. The holding member spontaneously falls off and is discharged after the ligature wire is cut.
[Patent Document 1] Japanese Unexamined Patent Publication No. 2003-204966